current genetic topics

Current Genetic Topics

Disorders, Cloning, Gene Therapy

Atypical meiosisIf something wrong happens during meiosis, this can impact many things.If there is an error in the chromosomes, ALL the cells will be affected.

NondisjunctionNondisjunction: the failure to separate.

When two homologous chromosomes move to the same pole during meiosis instead of moving to opposite poles.One of the resulting cells ends up with a chromosome missing, while the other has an extra.These cells will not work as they should.

NondisjunctionWhen a fertilized egg with an abnormal number of chromosomes divides, each cell in the body will also have an abnormal amount of chromosomes.

In most cases, the zygote will die.However, sometimes a person with nondisjunction disorder is born.

Down SyndromeAn extra chromosome for chromosome pair 21 – too much genetic information.

Turner SyndromeOccurs when sex chromosomes undergo nondisjunction in the male or the female parent.Produces a female with one X chromosome instead of two.

Do not mature sexually and are often are small in stature.

Klinefelter SyndromeNondisjunction in egg or sperm cellInherits two X chromosomes and one Y chromosome

The resulting baby will be a male, but during puberty will begin to develop high levels of female sex hormonesThese males are sterile.

Genetic ScreeningGenetic screening is a process by which a doctor draws amniotic fluid from the sac that surrounds the fetus.

This fluid contains cells which doctors can now screen and determine whether the baby will be born with a genetic disorder.

https://www.youtube.com/watch?v=8eR4XdJSmqc

Genetic Screening in Canada

http://healthycanadians.gc.ca/health-sante/pregnancy-grossesse/gen-test-eng.php

Genetic ScreeningFlip to page 225 and break into groups of 2.Read through the points and counterpoints and then work through the “What do you think” section.

Eliminate the 3rd point.Discuss these points as a class.

CloningWhat comes to mind?

CloningCloning is a natural process that happens often in nature

Examples?Binary Fission – the mother cell splits into two identical daughter cellsBudding, vegetative reproduction, etc

CloningCloning is the process of forming identical offspring from a single cell or tissue.ASEXUAL REPRODUCTION

Cloning a PlantFrederick Stewart had great success taking a single carrot cell and growing it into a plant.Isolated a portion from the root tip of the carrotThe key to success in cloning plants is to slow down the specialization process of the cells

Ex. Leaf cells, root cells, stem cells

Cloning AnimalsRobert Briggs and Thomas King successfully cloned a frog.

Extracted nucleus from an unfertilized egg cellNext, a nucleus was extracted from a frog embryo in early development

This nucleus was inserted into the unfertilized egg cell.

Mammal CloningSee diagram on page 196

Dolly

Dollyhttp://www.nytimes.com/2013/10/14/booming/the-clone-named-dolly.html?_r=0Dolly was different because the clone originated from taking cells from an FULLY DEVELOPED SHEEP.See diagram on page 197

Stem CellStem cells are very special, powerful cells found in both humans and non-human animals. They have been called the centrepieces of regenerative medicine – medicine that involves growing new cells, tissues and organs to replace or repair those damaged by injury, disease or aging.Source:http://www.stemcellnetwork.ca/index.php?page=what-are-stem-cells

Gene TherapyGene therapy is an experimental solution for treating disease by changing the patient's genetic material. Most often, gene therapy works by introducing a healthy copy of a defective gene into a person’s cells.http://www.bbc.com/news/health-26473802

DiscussionThink-pair-share

Has science gone too far?Should we continue with cloning, gmos, genetic screening?Should governments be allowed to dictate whether this science is